As @one_eyes notes - http://www.medtech3000.de still provide the DBC in latex material (in fact manufacture as well as own the Rusch patent) Their standard being very high with quality control, as is their approach to consumer marketing & customer satisfaction.
Medtech / Rusch are reputable organizations accredited with supplying these products to both the GDR & Austrian medical faculties, plus they do ship worldwide
Link below takes you to all their available Balloon Catheters individually, also including size specifications, stock inventory codes & cost @ pos:
http://www.zity.biz/index.php?mx=forum;ox=display;msg=759022
As @Switchablesusie points out, personal / private useage would fall at the lower end of the consumer /sales spectrum
Not sure whether www.medicaltoys.com/enemas.htm still have DBC's at their disposal. An email can resolve any enquiry
Another mentioned (zity link above) http://www.vetmedusa.com .Who'd carried them for a time & may no longer be available, the product appeared to be the Cleanstream replica in silicone ??
Cleanstream reviews of their product suggest a poor level in failure rate, greater than that of their counterparts
There could be a resurrection of the Klystra DBC by way of siliconenozzles.com,which would be rebranded & dependant upon the tooling required. .Though it's an unknown factor based on some discussion here as they had been in negotiations with either Klystra's former owner(s) come operator or estate. .Whether it comes to fruition is anybody's guess